| AIMSAs a result of trauma, tumor excision and other reasons caused by the cartilage defects and repair, the current treatment is using autogeneic / allogenic cartilage transplantation. However, as the source of autologous cartilage tissue is limited, and the donor could cause secondary trauma; the source of allograft cartilage tissue has the risk of immune rejection, it is difficult to reach a very desirable effect. In recent years, the clinical treatment of tissues and organs defect based on the stem cells as seed cells in vitro with certain shape and biological function of tissue-engineered tissues and organs gradually become research hot spots. In order to provide experimental evidence and theoretical basis for the repair of cartilage defects, we combined human placenta-derived mesenchymal stem cells (hPDSCs) with the collagen sponge scaffold to build tissue-engineered cartilage tissue and observed its ability to form cartilage tissue in vivo and in Vitro. Methods:1. To obtain hPDSCs and detect its biologocal characteristics.Human placenta- derived mesenchymal stem cells(hPDSCs) were obstained, cultured and expanded by using trypsin digestion, then we analyzed the biological characteristics of hPDSCs through morphological observation, cell cycle detection, surface markers analysis, karyotype analysis and tumorigenicity in nude mice; meanwhile, we observed the differentiation of hPDSCs to the cartilage cells under certain medium through morphological observation, immunohistochemical stain and RT-PCR detection on type II collagen.2. Construction of tissue-engineered cartilage based on hPDSCs as seed cellsWe constructed the protocol of collagen sponge derived from fresh healthy ox tendon in vitro, then the collagen sponge were covered by hPDSCs according to certain density in order to observe the feasibility of tissue engineering cartilage construction based on the combination of hPDSCs and collagen sponge cultured under conditioned medium, then we observed the implanted tissue-engineered cartilage in vivo through gross specimen and histological detection, immuno- histochemistry analysis of type II collagen.Results:1.hPDSCs could be obstained,cultured by using trypsin digestion, cultured cells had stable growth and the passage. hPDSCs grew rapidly and its doubling time was about 34 hours in vitro; hPDSCs had excellent proliferation ability, in vitro culture for more than 30 generations, it had no signs of phenomenon for self differentiation. By using flow cytometry, hPDSCs revealed that over 90% of the hPDSCs were in G0/G1 (stationary) stage, surface markers of hPDSCs demonstrated that hPDSCs had expression of CD44, CD29, CD90, did not express the hematopoietic cell surface markers CD34, CD45 and CD106, indicating that hPDSCs showed the biological characteristics mesenchymal stem cells. hPDSCs showed safety and good genetic stability based on karyotype analysis and no tumorigenicity.2.hPDSCs could differentiate into chondrocytes under certain medium in vitro, it indicated that hPDSCs might be good seed cells sources for tissue engineering cartilage construction.3.It had been confirmed that the prepared collagen sponge scaffolds had great biocompatibilityand and biological function.The results showed that hPDSCs with collagen sponge compound successfully differentiate into cartilage tissue with certain shape and function in vivo.Conclusion:1. hPDSCs has a good ability of self-renewal and differentiate into chondrocytes, hPDSCs could serve as the good seed cells source for construction of tissue engineering cartilage;2. Prepared collagen sponge scaffolds had great biocompatibilityand and biological function, hPDSCs with collagen sponge compound successfully differentiate into cartilage tissue with certain shape and function in vivo and in vitro. It provided experimental evidence and theoretical basis for the repair of cartilage defects.
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